Lecture 10 - Invertebrate Life History part 1 Flashcards
The ideal animal
- Mature at birth and reproduces immediately
- Continually produce large numbers of high-quality offspring
- Live indefinitely
What if life history?
An individual’s pattern of allocation, throughout life, of time and energy to various fundamental activities such as growth, maintenance and reproduction
Life History traits
Traits that affect an organism’s schedule of reproduction and survival.
Life History trait examples
Clutch/litter size Incubation/gestation length Offspring size Sex ratio Presence, degree of length of parental care Growth rate Age and size at maturity Adult body size Frequency of reproduction
Life History constraints
Genetic architecture
Phylogenetic history
Biophysical and mechanical factors
Life style
Darwinian demon
A hypothetical organism that could maximise all aspects of fitness simultaneously, if the evolution of a species was entirely constrained
life history trade offs
negative relationships among growth, reproduction, and survival
Life history trade off examples
Age vs size of maturity Current vs future reproduction Reproduction vs survival Reproduction vs growth Growth rate vs lifespan Clutch size vs egg size Parental vs mating effort
Life History strategies
r/K selection theory
r-selected individuals
Production of a large number of offspring as early in life as possible
Live fast, die young
K-selected individuals
Production of a smaller number of fitter offspring with higher chances of survival
Reproductive strategies
Iteroparity and Semelparity
Iteroparity
Where organisms produce offspring in a series of separate events during and after which the organisms maintain themselves in a condition that favours survival to subsequently reproduce again (K-selected)
Iteroparity in simple terms
They ** multiple times, have small amounts of offspring but large
K-selected individuals
Semelparity
Where organisms produce all their offspring in a single reproductive event over one relatively short period (r-selected)